Automatic drain valve



21, 1931-. Q C, FARMER 1,801,853

` AUTouATIc DRAIN VALVE Filed June 15. 192e ggg Wm/M ATTORNEY Patented Apr. 21, 1931 UNITED STATES PATENT OFFICEN 'GLYSDE C. FARMER, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 THE lWES'JIJTG- HIOUSE AIR :BRAKE COMPANY, OF VIILMERDING, PENNSYLVANIA, A CORPORATION PENNSYLVANIA AUTOMATIC DRAIN VALVE f lApplication filed. June 1 3, 1928. Serial No. 284,895.

This invention relates to automaticy drain valves for draining the steam cylinders 'of a fluid compressor and also for draining the .main reservoir of the fluid pressure brake system.

One object of my invention is to provide a drainvalve device operated upon a predetermined reduction in brake pipe pressure for draining thesteam cylinders kof a fluid compresser.

, ,Another object of myinvention is to provide a Vdrain valve device, the operation of which is dependent upon the joint action of brake pipe pressure and the pressure in the main reservoir for controlling the draining fof the main reservoir.V

4 Other objects and advantages will appear in the following more detailed description of the invention. v

' In the accompanying drawing; Fig. is a diagrammatic view, partly in section, of a steam driven fluid compressor equipment, showing the improved drain 4valve device associated therewith; and Fig. 2 a sectional,

view of a modified form of the main reservoir drain lvalve device.

In the drawing, a compound steam driven iiuid compressor 1 is'shown having a high pressure steam cylinder 2 and a low pressure steam cylinder 3, of the type commonly employed on railway locomotives. The high pressuresteam piston 4 is connected by piston rod 5 to the low pressure iiuid compressing piston (not shown) contained in cylinder 16 `and the low pressure steam piston (not shown) is connected bya piston'rod'f with the high pressure fluid compressing shown) contained .in cylinder 8,." z y The drain valve device may comprise a casing 9, having a piston chamber connected to the usual brake pipe 11 of the fluid pressure brake system and containing a piston 12. Said piston is provided with a piston stem 13, carrying a pin 14, which extends into a piston (not recess in a slide valve 15, said slide valve being mounted in a valve chamber 16.

:The valve chamber 16 is connected through wpipe `17 and passages in the compressor casing, with the steam supply pipe 18 of the compressor and pipes 19 and 20, connected respectively to the high and the low pressure .through an opening in a partition wall 3l and is adapted to engage the diaphragm 22. The chamber 32 above thevalve piston 28 is open to the atmosphere through a passage 33 and chamber 34 at the other side of the valve piston contains a spring 35 which urges the valve piston 28 upwardly, the'chamber 34 being open to the atmosphere through passage 36.

Mounted in the drain valve casing 9 is a doublebeatvalve 37 adapted in one position Vto connect passage 38, communicating with chamber .23, toa passage 39, which is connected through pipe 40 with the main reservoir 27. In the other or opposite position, passage 38 and chamber 23` are vented to the atmosphere by wayof passage 41.

Connected to the double beat valve 37 and extending through the passage 41 is a rod 42, whichextends through anv opening in an arm .43, carried by the pistonlstem 13. Secured to the rod 42 at opposite sides of the arm 4 3 Yare disks 44 and 45 and interposed between the arm 43 and the disks 44 and 45 are springs 46 and 47 respectively. l

' A spring 48 acts o n piston l2 and is adapted to be compressed at a predetermined pressure in the brake pipe acting on piston 12, to permit movement of the piston to its right hand position. lVith the piston 12 in this position, the slide valve 15 blanks the passages leading to pipes 19 and 20 and the double beat valve 37 is held seated in its right hand position, so that Huid at main reservoir pressure is supplied to diaphragm chamber 23. The opposite side of diaphragm 22 being exposed to main reservoir pressure, the spring 24 will hold the diaphragm to a seat, so that communication from pipe 26 to' chamber 32 is cut off.

If the brake pipe pressure is reduced below a predetermined degree, for example, twenty pounds, as would be the case when a locomotive is not being used or when an emergency application of the brakes is effected, the piston 12 will be shifted to its left hand position in which a cavity 49 in slide valve 15, connects pipes 19 and 2O with an atmospheric exhaust port 50. vWater in the steam cylinders 2 and 3 is then drained out through the exhaust port and a port 51 being provided which connects valve chamber 16 with cavity 50, water draining from the steam supply pipe of the compressor into the valve chamber 1G will also escape by way of exhaust port 50.

The double beat valve 37 will be shifted by the movement of piston 12to its left hand position, so Vthat communication is cut off Vfrom the main reservoir to chamber 23, while said chamber is vented to the atmosphere by the movement of the double beat valve from its right hand seat.

l/Vhen fluid pressure is vented from chamber 23, if the main reservoir pressure exceeds j a predetermined degree, for example, forty pounds, the springs 24 and 35 are such that the main reservoir pressure acting in chamber 25 will shift the diaphragm, so that the valve piston 28 will be permitted to seat and cut off communication from chamber 25 to chamber 32.

If the main reservoir pressure should fall to the predetermined pressure o'f forty pounds, as would be the case when the locomotive is not in service, the diaphragm will move downwardly so as to unseat the valve piston 28. Water in the main reservoir 27 will then be drained out by way of the vent port 33 and the vent will remain open until the main reservoir pressure has fallen sufficiently to permit the diaphragm 22 to engage its seat, at a pressure, forexample, of thirty pounds.

By causing communication from the main reservoir to the vent port 33 to be cut oi when the main reservoir pressurefallsbelow a predetermined degree, ensures that when the compressor is again started, the main reservoir pressure may be pump'ed'up,`with out pressure escaping at the Vvent port 33.

When the compressor is ruiming and the pressure in the main reservoir is being increased, the brake pipe pressure is also raised and when the brake pipe pressure has been increased to the predetermined pressure, the piston 12 is shifted to its right hand position, in which the double beat valve is moved so as to connect the main reservoir with the diaphragm chamber 23. The diaphragm is then held seated, while the main reservoir pressure is beingincreased to the vstandard pressure carried.

With the modified construction shown in F ig. 2, the spring 24 acting'on diaphragm 22 is such that when the "fluid pressure is vented from chamber '23', it will require a high main'reservoir pressure acting in chamber 25 below the diaphragm to unseat the diaphragm, for example, one hundred pounds or more.

Vith this construction, when Vthe diaphragm 22 is unseated, water is drained directly at port 52, which opens to the atmospliere.

With the modified construction, if it is desired to drain the main reservoir, the engineer makes an emergency reduction fin brake pipe pressure and thus causes'the piston 12 to move to its left hand position and thereby the double beat valve 37 is operated to vent iiuid under pressure from-the diaphragm chamber 23. If the main reservoir pressure 1s at this time in'eXcess of one hundred pounds pressure, as would usually be the case when the locomotive is in service,

'diaphragm 22 will be operated to cut 0H.

communication fromthe main reservoir `to the drain port 52.

While one illustrative embodiment of the invention has been described in detail, it is Vnot my intention to limit its scope to that embodiment or otherwise than by the terins of the appended claims.

Having now described myinvention, what I claim as new and desire' to 4secure by Letters Patent, is :V

l. The combination with a main `reservoir and a brake ,pipe of a iiuid pressure brake system, of a valve device operated upon a reduction in main reservoir pressure vto a predetermined degree for opening communication through which liquid is vented from said reservoir and upon a further reduction in 'main reservoir pressure to a lower predetermined degree for cutting'oif said communication, and means operated by variations in brake pipe pressure for also controlling the operation of said valve device.

2.V The combination with a main reservoir, of a drain valve device comprising a diaphragm subject on one side to main reservoir pressure, a spring opposing the main reservoir pressure on said diaphragm, said diaphragm being operated upon a predetermined reduction in main reservoir pressure for closing communication from the main reservoir to a drain port, and means operated upon a predetermined increase in main reservoir pressure Jfor also closing communication from ,the main reservoir to the drain port.

3. The combination with a main reservoir,

4of a drain valve device comprising a diaphragm subject on one side to main lreservoir pressure, a spring opposing the main reservoir pressure on said diaphragm, said diaphragm being operated upon a predetermined reduction in main reservoir pressure for closing communication from the main reservoir to a drain port, and means operated upon a predetermined increase in main reservoir pressure for also closing communication from the main reservoir to the drain port, said drain port being open to the main reservoir during the movement of the diaphragm between the positions for closing communication from the main reservoir to the drain port.

4. The combination with a steam driven fluid compressor and a brake pipe of a Huid pressure brake, of a valve for opening a drain for draining liquid from the steam cylinder of said compressor, and a piston subject to brake pipe pressure and operated upon a reduction in brake pipe pressure for operating said valve.`

. 5. The combination With a steam driven fluid compressor having tWo steam cylinders and a brake pipe of a fluid pressure brake system, of a valve for draining liquid from said steam cylinders, and a pistonrsubject to brake pipe pressure and operated' upon a reduction in bra-ke pipe pressure for operatp ing said valve.

6. The combination with a main reservoir, of a diaphragm subJect to main reservolr pressure, and valve means operated by said diaphragm upon a predetermined reduction f in main reservoir pressure for draining liquid from said reservoir, said valve means being operated by a further movementy of said diaphragm upon a further reduction in main reservoir pressure to cut oii communication through Which liquid is drained from said reservoir. Y

7. The combination With a steam drive Y fluid compressor having a steam cylinder, and a main reservoir and a brake pipe of a Huid pressure brake system, of a valve device operated upon a predetermined reduction in brake pipe pressure for draining liquid from said steam cylinder, valve means operated 

